Comparison of electromigration in Cu interconnects with ALD or PVD TaN liners

Abstract

Electromigration in 0.07 μm wide Cu interconnections has been investigated for the sample temperatures from 213°C to 300°C. The effect of atomic layer or physical vapor deposited TaNx and physical vapor deposited Ta liner layers in Cu Damascene lines on electromigration was also studied. A lower lifetime and activation energy for electromigration was observed in tested lines with sidewall voids. Similar electromigration lifetime and activation energy observed from samples with either atomic layer deposited or physical vapor deposited TaNx suggested that the dominant diffusion paths in the Cu lines were not sensitive to the TaNx layer and were along Cu/dielectric interface and/or grain boundaries. copyright The Electrochemical Society.